Water-Microdroplet-Driven Interface-Charged Chemistries

Water has made Earth a habitable planet by electrifying the troposphere. For example, the lightning caused by the electrification and discharge of cloudwater microdroplets is closely related to atmospheric chemistry. Recent work has revealed that a high electric field exists at the interface of water microdroplets, which is ∼3 orders of magnitude higher than the electric field that accounts for lightning. A surge of exotic redox reactions that were recently found over water microdroplets can be contributed by such an interfacial electric field. However, the role of net charge in microdroplet redox chemistry should not be ignored. In this Perspective, we show how redox reactions can be driven by electron transfer pathways in the electrification and discharge process of water microdroplets. Understanding and harnessing the origin and evolution of charged microdroplets are likely to lead to a paradigm shift of electrochemistry, which may play an overlooked role in geological and environmental chemistry.